Telegraph exchange system



5 Sheets-Sheet l Filed Aug. 3, 1940.`

0t.1s,1949. -GGUGHT ETAL 2,484,838-

TELEGRAPH EXCHANGE SYSTEM -Fi'led Aug.l3, 1940 5 Sheets-Sheet 2 SECOND CORD CIRCUIT INVENTORS G.G. LIGHT O NEY oct. 18, 1949.

G. G. LIGHT s-:rAL

- TELEGRAPH EXCHANGE SYSTEM 5 Sheets-Sheet 3 Fue@ Aug. s; 1940 INVENTORS G. G. LIGH T BY BLAN TON ATToQNEY Oct. 18, 1949 G. G. LIGHT Erm; 8 2,484,838

TELEGRAPH EXCHANGE SYSTEM Filed Aug. s, l194.65 5 sheets-sheet 4 Q' A. INVENTORS GGLIGHT A 0 BY /.BLANTON ATTGNEY --TO FIG. 3-

Oct. 18, 1949.. G. G. L xGHT ET AL 25,434,838

TELGHAPH EXCHANGE SYSTEM Filed Aug. 3, 1940 5 Sheets-Sheet 5 fflNvEN-roRs G. G. L l GHT BY BLANTON ATT RNEY Patented Oct. 18, 1949 UNI-TED STATES PATENT OFFICE TELEGRAPH EXCHANGE SYS TEM Application August 3, 1940, Serial No. 350,402

20 Claims. l

This invention relates to telegraph exchange systems and more particularly to systems of this character in which telegraph lines or channels are interconnected under the control of a switchboard operator or attendant at the exchange.

Line switching systems for interconnecting telegraph offices or patrons under the control of a switching operator or attendant at an exchange are disclosed in the prior patents to Wheeler et al. 2,193,810 and Blanchard et a1. 2,193,811. granted March 19, 1940. In the systems disclosed in said patents, connections are made to outgoing lines or channels through a manual switchboard or equivalent switching equipment under the control of a switching operator. After connection has been made to a selected line or channel, transmission of the message is started as soon as the line or channel is available, and the line or channel is automatically released at the end of the message.

One object of the present invention is to enable the switching operator in a system of the above-described character to select at a remote point any desired one of a plurality of receiving or repeating units whereby messages sent over a single outgoing line circuit may be switched to separate receiving or terminal points. Each line circuit or channel preferably is provided with a` plurality of switching terminals or switchboard jacks at the exchange and, in accordance with another feature of the invention, the particular jack or terminal selected by the operator determines the selection at the remote point without requiring the operator to send a selection code or a series of controlling impulses for switching the call.

The above-mentioned patents also disclose means for automatically transmitting service code signals accompanying successive messages sent over outgoing trunks or channels. Thus, for example, the messages transmitted over any particular line or channel may be numbered with consecutive numbers to facilitate the checking cf accurate transmission and enable messages tc be re-transmitted when desired. In accordance with another object of the present invention, means is provided for automatically transmitting consecutive numbers `accompanying each series of messages toa particular destination even though the messages to different points may be transmitted over a common line circuit or .channel. In this manner the messages for different destinations are numbered #consecutively in each instance 4even though l'certa-in messages for .dif-

2 ferent destinations are sent over the same line circuit or channel.

Another object of the invention is to provide an improved selector for telegraph communication which is controlled over the line circuit or channel used in the transmission of intelligence signals.

A still further object of the invention is to interlock the transmitting or repeating equipment sharing a common channel to prevent transmitting equipment from seizing a channel which is already in use or interfering with transmission in progress over said channel.

Other objects and advantages of the invention will become apparent from the following description of a preferred embodiment thereof shown in the accompanying drawings, wherein Fig. 1 is a condensed diagram of the system; and

Figs. 2 to 5 are detailed circuit diagrams of the system shown in Fig. 1.

Referring to Fig. 1, a system embodying the invention may comprise a manual switchboard or equivalent means for connecting printing telegraph transmitters or repeating equipment to selected outgoing line circuits or channels. As shown, tape perforators Il and l2 representing any sources of signals to be transmitted through the telegraph system have associated therewith tape transmitters 2l and 22 for repeating the signals stored in the tape through the cord circuits and connecting plugs 3l and 32. The switchboard in the arrangement shown'for purposes of illustration comprises a plurality of sections represented by the switchboard jacks lll, 42, 43, lila, 42a, 43a, into which the connecting plugs shown are inserted to extend connections from the tape transmitters to selected outgoing line circuits. It will be understood that the switchboard may include any number of sections and the corresponding jacks of each section are multipled together, and that while only the three switchboard jacks at each section of the switchboard associated with a single loutgoing line circui-t Ll are show-n, as many cord circuits and switchboard terminals are provided as are required to handle the traffic through the exchange.

Each series of multpled switchboard jacks or lin-e terminals of the line Ll is provided with a code transmitter or numbering machine NMI, NM2, NMS, in order that the messages for diiferent destinations transmitted over the line Ll may Joe consecutively numbered in each instance. .At the remote .end of the line Ll a selector 10| is tember 5. 1939.

provided which is controlled by signals transmitted by the numbering machines. Thus if the cord circuit of any transmitter, such as the transmitter 2I in cord circuit 3I, having a message to transmit, is plugged into the jack 4I, the numbering machine NMI transmits a code which contains the number of the message and which leaves the line circuit LI connected to the printer I5I. If, however, the cord circuit is plugged into the jack 42 or 43, the selector IIJI connects the line circuit LI to the reperforator I 6|, and the message is numbered depending upon the number of the last message sent over the line LI destined foreither the line L2 or L3 to which connection is to be made through the reperforator IBI and its associated tape transmitter I1I.

The local operator at the remote oflice notes the address of the message received on the reperforator IBI incase the repeating apparatus is intended to work into more than one line and selects the proper line by throwing the switch IBI. Each of the lines L2 and L3 have keyboards or local transmitters i12 and |13 respectively associated therewith, whereby the operator may transmit messages over said lines when the repeater is not connected thereto. The switches 132 and |83 are provided for connecting the lines L2 and L3 either to transmitter I1I or to the local keyboard with interlocking features to prevent operation of the keyboard if the tane transmitter I1I has not released the transmitting circuit and to prevent the selection of the line by the switch I3! from rendering the tape transmitter I1I operative if the line has not been released from the local keyboard.

Detailed description of the cord circuit The detailed circuits of the system shown in Fig. 1 are shown in Figs. 2 to 5, Fig. y2 representing a cord circuit arranged to extend the connection from the tape transmitter 2| through connecting plug 3i to the switchboard.

Referring to Fig. 2, it will be noted that only the Acomplete circuit diagram of one cord circuit is shown, the cord circuit associated with the second tape transmitter 22 being indicated diagrammatically since it is identical with the cord circuit associated with the tape transmitter 2|.

The tape connected to the tape transmitter 2I may be perforated by a printer perforator such for example as that shown in the patent to Dirkes et al., 2,174,731, granted Octoiber 3, 1939. The tape transmitter may be similar to that shown in the patent to Angel, 2,172,269, granted Sep- A distributor trans-mitter 4I) is operatively associated with the tape transmitter ZI, said distributor transmitter being similar in construction to that shown in the patent to Rothermel, 1,805,374, granted May 12, 1931, and comprises a series of contacts which are opened and closed at a predetermined time in order to control the operation of the tape transmitter and to time the transmission of the code impulses from the tape transmitter through the transmitting circuit including the tip contact of the connecting plug 3I.

The operator notes the destination of each message received and inserts the plug 3I in the proper switchboard jack. As soon as the selected circuit becomes idle, the tape transmitter is rendered operative to repeat the message stored in the tape over the selected circuit in a manner similar to that disclosed in the above mentioned patents to Wheeler et al. and Blanchard et al. Each message is terminated by an end-of-message signal which stops transmission and releases the line circuit. In the particular system shown by Way of example, the end-of-message signal consists of a double carriage return (fourth impulse only marking) and each message is spaced from adjacent messages by atleast six unshifts (all marking code combinations).

As shown, the marking bus bar of the tape transmitter is open circuited and the spacing bus lbar 24 is connected to ground through circuits to .be described below so that marking impulses are represented by zero current and spacing impulses by ground potential. The selectively operable contacts of the tape transmitter are connected respectively to the 'windings of relays 25, 26, 21, 28 and 23, so that said relays become energized when each contact engages the spacing bus bar. The storing relays 25 to 29 are thus operated in response to spacing impulses from the transmitter 2|, and said relays control transmission of the permutation code signals through the cord circuit and switchboard, converting the marking impulses of the code into current impulses and the spacing impulses of the code into nocurrent impulses. The autostop contacts associated with the loop of tape between the reperforator and the tape transmitter are indicated at 45, said contacts being open when the tape loop becomes taut and being closed when the tape loop lengthens when a message is received on the reperfcrator.

When the cord circuit is not in use, the circuit of the spacing [bus bar 24 of the tape transmitter may be traced through the right hand winding of relay 34, the normally closed contacts of the make-before-break contacts associated with the outer left hand armature :of relay 36 and the right hand inner armature and back contact of relay 31 to ground. When a message is received on the reperforator associated with the tape transmitter 2|, the contacts 45 close in response to the lengthening of the tape loop and close a circuit for energizing the clutch magnet of the distributor transmitter 40 which may be traced through the right hand armature and back contact of relay 34 and the second left hand armature and Iback contact of relay 36. The clutch magnet of the distributor transmitter 4c releases its cam shaft for one revolution thereby closing the circuit to the stepping magnet of the tape transmitter 2I through a circuit including the winding of relay 33, the left hand outer armature and back contact of relay 34, and the eighth contacts 62 of the distributor transmitter 43. The contacts 62 close momentarily at the end of the fifth pulse of the code transmitted by the transmitter 2| under the control of the distributor transmitter. Relay 33 becomes energized and locks up through a circuit including its right hand inner armature and front contact that is independent of the contacts of relay 34. When the stepping magnet of the tape transmitter 2i is energized, the pins are Iwithdrawn from the tape and the contacts are all actuated into engagement with the spacing bus bar whereupon relay 34 becomes energized through the above described circuit to the contacts of the tape transmitter and thnough said 'contacts and the windings of relays 25, 2B, 21,

mesma the character in the tape is the unshiiI or all marking code combination, all of the contactsof. the tape transmitter engage the marking busv bar, thereby opening the circuit of relay 34 and said relay lbecomes deenergized to re-operatey the distributor transmitter 33? and the tape transmitter 2i in the same manner as described above. In this manner the series of unshiff code come lbinations perforated in the tape between mcs-- sages are stepped through the tape transmitter without waiting for the connection to: be made: at the switchboard. However, as soon as the' rst code combination other than the all-mark-- ing code combination reaches the pins of the tape transmitter, relay 34 remains energized since: at least one impulse of the code is'spacing, there- \by holding the circuit of the clutch magnet of? the distributor transmitter' 4B open. A circuit is now closed through the second left hand` arma` ture and back contact of relay 35, the right hand armature and front contact of relay 34, and the left hand armature and back contact of relay 33 for lighting the message waiting lamp 35 to indicate that a message has been received for retransmission through the switchboard.

When the operator plugs into the switchboard jack, a circuit is closed as will be described in detail hereinafter connecting battery potential through the ring contact of the switchboard jack, the winding of relay 41, second left hand armature and back contact of relay 48 and contacts of the interrupter 43 to ground, whereupon relay 41 becomes energized if the line circuit is idle. As explained in the above mentioned Blanchard patent, the purpose of the interrupter 49 and guard relay 41 is to prevent the cord circuit from transmitting to a busy line and to connect each one yof a plurality of cord circuits plugged into' the same line for operation one after the other. Assuming that the line circuit is idle, relay 41 locks up through a circuit including its right hand inner armature and front contact, the sec'-4 ond left hand armature and back contact of relay 5i that is independent of the contacts of the interrupter a9. Thus a low resistance connection to the ground is provided for the ring contact of the switchboard jack which serves as a guard potential for the multiple jacks of the same line circuit.

Upon the energization of relay 41 a circuit is closed from ground upon the sleeve conductor through the right hand outer armature and front contact of relay 41 for energizing relay 48; said relay locks up through its left hand inner armature and front contact directly to the sleeve contact of the connecting plug 3|. Upon the energization of relay 41 a circuit is also closed through its left hand inner armature and front contact for energizing slow release relay 52 and `said relay locks up through its left hand armature and front contact to ground at the left hand inner armature and back Contact of relay 5i. The energization of relay 52 closes a circuit from ground through the right hand armature and iront contact of said relay for energizing relay 36 whereupon the line circuit is closed to the tip contact of the connecting plug 3l through a circuit which may be traced from the left hand inner armature and front contact of relay 35, the winding of relay 53 and the normally closed or rest contacts of the distributor transmitter u to battery. It will be understood that the rst five contacts of the distributor transmitter which are connected to battery in parallel with the rest contacts serve to time the ve code impulses set up on the contacts of the 65 tape transmitter and thereby transmitl thel code impulses in'y succession through the transmitting circuit just described including the tip contact of the connecting plug 3|.

The energization of relay 36 closes through its; right hand armature and front contact a second locking circuit for relay 41; opens at the contacts associated with the outer left hand armature of said relay the circuit of the clutch magnet of they distributor transmitter 40 employed for idling the un-shift code combinations through the tape transmitter; opens the circuit of relay 34 and` transfers the circuit of the spacing bus bar24 of the tape transmitter 2| to ground through a circuit that is independent of relay 34. The cord circuit is now in readiness to transmit when the control relay to be referred to hereinafter is operated. This closes the transmitting circuit through the tip of the switchboard plug to battery at the contact-s of the distributor transmitter 40 whereupon relay 53 becomes energized and closes a circuit through its armature and front contact,

the right hand outer armature and back contact of relay 55,.` the winding of relay 56v and the left handv outer armature and back contact of relay 5i whereupon relay 56 becomes energized and closes a circuit through its left hand outer armature and front contact for shunting out the winding' of relay 53 from the line circuit. Relay 56 locks up through a circuit including its left hand armature and front contact and the first bank contact of the second switch wiper of the stepby-step switch 60. The energization of relay 56 also closes a circuit for energizing the clutchmagnet of the distributor transmitter 40 which circuit may be traced through said clutch magnet, contact 45, the right hand outer armature and back contact of relay 31, the left hand outer armature anci front contact of relay 41, and theA right hand armature and front contact of relay 56.y Thereupon the distributor transmitter 40 is rendered operative to control the stepping of the tapev transmitter for transmission of the successive characters in the message through the line circuit described above including the tip contact of the switchboard plug 3|.

As stated above, successive special code combinations Such as No. 4 marking (carriage return) are appended to the message as an endof-Inessage signal, followed by at least six unshifts for spacing messages in the tape. When a character having only the fourth impulse marking reaches the pins of the tape transmitter 2l, relays 25, 26, 21 and 29 will be energized and relay 28 deenergized. When the contacts 6i of the distributor transmitter 45 close during the fourth pulse (remaining closed until the end of the iifth pulse) a circuit is closed through the left hand outer armature and back contact of relay 31, the right hand outer armature and front contact of relays 25, 26, 21 and 29, the right hand outer armature and back contact of relay 28, the armature and back contact of relay @-5, the winding of relay 66, the armature and back contact of relay 61 to battery, whereupon relay 65 becomes energized. When the contacts 5i of the distributor transmitter open at the end 0f the :fifth pulse, relay 65 becomes energized through a circuit that may be traced through the inner armature and locking contact of relay 5t and winding of relay 65, and the third left hand armature and front contactl of relay 35 to ground. If the following character is not a carriage return, a circuit is closed upon receipt of this character for energizing relay 61 through the left hand outer arma- 7V ture and front contact of relay 65, and the outer armature. and back contact of one of the relays 25, 26, 21 or 29, the left hand outer armature and back contact of relay 31 and the contact 6| of the distributor transmitter lill, whereupon relay 61 becomes energized and releases relays 65 and 66. If, however, two carriage returns are transmitted in succession, a circuit is closed through the contacts of relays 25 to 29, the armature and front contact of relay 65, and the winding of relay 55 for energizing the latter relay. When the contacts 6| open, relay 31 operates in series With the locking contact of relay 55, relay 31 operating at substantially the end of the fifth pulse of the ysecond carriage return signal. The energization of relay 55 as described removes a short circuit through its left hand outer armature and back contact around the winding of relay 53 and closes a circuit through its right hand inner armature and front contac-t to the left hand winding of relay 3ll to cause the latter to operate and lock up when relay 33 operates. The energization of relay 31 as described opens at its outer right hand armature and back contact a circuit through the autostop contacts 45 for controlling the clutch magnet of the distributor transmitter d0. The energization of relay 31 also opens at its inner right hand armature and back contact the ground connection to the spacing bus bar of the tape transmitter so that if the distributor transmitter lil is operated, unshifts or all-marking code combinations will be transmitted through the cord circuit to the line regardless of the position of the contacts of the tape transmitter. In addition, the contacts 9| of the distributor transmitter d@ are connected through the two left hand armatures and iront contacts of relay 31 to the operating magnet of the step-by-step switch 68 whereby the wipers of said switch will be advanced one step for each cycle of operation of the distributor transmitter until the relay 31 is released. The distributor transmitter 48 is now operated since the circuit of the clutch magnet thereof is closed through the right hand outer armature and front contact of relay 31, the left hand outer armature and front contact of relay 81, and the right hand armature and front contact of relay 56 to ground. During each rotation of the cam shaft of the distributor transmitter an unshift or al1-marking code combination is transmitted to the line and the wipers of the step-by-step switch 68 are stepped from one bank contact to the next. The tape transmitter 2| remains inoperative and no talle is stepped therethrough during the transmission of these unshift code combinations. At the end of the fth all-marking code combination, the switch wipers of the switch 88 step intok engagement with their sixth contacts and the holding circuit of relay 56 is opened at the second switch wiper of said step-by-step switch. However, relay 56 remains locked up through its left hand inner armature and front contact and the right hand outer armature and front contact of relay 55 to ground at the armature and front contact of relay 53 until relay 53 opens upon the start pulse of the sixth all-marking code combination. The deenergization of relay 56 opens at its right hand armature the circuit of the clutch magnet of the distributor transmitter lill and its cam shaft stops at the end of the sixth unshift code combination. Thus the wipers of the step-by-step switch 58 step into engagement with their seventh bank contacts at the end of the sixth all-marking code combination Aand a circuit is closed from ground through the s econd switch wiper, the seventh bank contact in engagement therewith, the Winding of relay 5| to battery, whereupon relay 5| becomes energized. Relay 5| locks up through its right hand armature and front contact to ground at the second left hand armature and front contact of relay 36. The energization of relay 5| opens the circuits of relays 41'and 52 whereupon said relays become deenergized, relay 52 closing a circuit through its right hand armature and back contact and the right hand armature and front contact of relay 48 for lighting the disconnect lamp 10. The deenergization of relay 52 releases relay 36 to open the line circuit and to release relays 31, 55, 65 and 66, which are locked up through the third left hand armature and front contact `of relay 36. Relay 52 is slow to release in order to permit relay 36 to hold up until the release of the relays associated with the line circuit has placed idle battery back on the line to prevent a momentary interruption'of the line circuit.

Line circuit control and transmission by numbering machine Referring to Figs. 3 and 4, when the plug 3| is inserted in the jack 4|, a circuit is closed through the upper make contacts of said jack and the winding of relay 8|. Upon the energization of relay 3| a circuit is closed from ground through relay 41 of the cord circuit, the ring conductors of the plug and jack, the winding of relay S2, the left hand armature and back contact of relay 33, the left hand outer armature and back contact of relay 84, the armature and front contact of relay 8|, the inner left hand armature and back contact of relay 84 and resistance 85 to battery. Relay 82 becomes energized and connects a shunt circuit including resistance 86 around the resistance to drop the voltage on the sleeve contacts of the switchboard jacks to condition the jack circuit at the time of disconnect until the control relays release. The energization of relay 32 closes a circuit through its inner right hand armature and front contact for initiating the operation of the numbering machine NM|. In a similar manner if the plug 3| has been inserted in jack 42, relay 82a would have been operated instead of relay 82 and the numbering machine NM2 would be rendered operative instead of the numbering machine NMI. Additional switchboard jacks, control relays and numbering machines may be provided as indicated.

In the system shown a single distributor may bel seized temporarily by any of the numbering machines while the number is being transmitted and then released for operation with other numbering machines, associated with either the same or another outgoing line. The switches 9| and 92 shown in Fig. 4 are utilized to temporarily associate the distributor 93 with a numbering machine, for example NMI in case the cord circuit is plugged into the jack-4|. The distributor 93 -may also be similar to that shown in the above mentioned patent to Rothermel. A second distributor may also be provided and when the busy key 94 is operated, the start circuit for the switches 9| and 92 is switched through the second key 94a to the second distributor control unit. The switches 9|. and 92 are arranged to connect the circuits of the distributor contacts to any of the numbering machines and therefore the description of the operation in connection with one of the machines will suffice. Upon energization of relay 82 as described a circuit is 9 closed from ground through the right hand in ner armature and front contact 'of relay 82, the third left hand armature and backjconta'ct of re'- lay 84, the left hand armature and back contact of relay 95, conductor 96, the normally closed contacts of the key 94, the armature and back Contact of relay 9'|, the right hand outer arma= ture and back contact 'of marginal relay 98and the right hand winding of relay 99 to battery. Relay 99 becomes energized and locks up through its right hand armature and front contact, the right hand armature and back contact of relay |03 and the winding of relay 91 to ground at the contacts of relay 82, which circuit is indepencl; ent of contacts of relay 98. Upon the energization of relay 99 a stepping circuit for the switch 92 is closed through the stepping magnet of said switch, the second left hand armature and front contact of relay 99, the left hand armature and back contact of relay Illll, the sixth switch wiper of the switch 92 in engagement with its first bank Contact, conductor |05, and the inner right hand arma-ture of relay 82 when said relay is deenergized. This causes the switch 92 to step over the contacts individual to relays 82, 82a, and so forth, which are not operated. Assuming, however, that the relay 82 is energized as described, the switch 92 will not step since the rst bank contact corresponds to the switchboard jack 4| and a circuit is closed through the stepping magnet of the switch 92 and battery, the left hand outer armature and front contact of relay 99, and the winding of relay |794 for energizing said relay to' ground the contact associated with the s i-X-th switch wiper' of the switch 9'2 so that other finder switches in multiple will not stop on the rst bank contact. The energization of relay `|94 also closes a cir-v cuit from battery through the winding of margi-` nal relay 98, the right hand armature and front contact of relay. |=94 and the winding of relay `||l'| to ground at the interrupter contacts asso# ciated with the stepping magnet of switch 9|. Marginal relay 98 does not become energized in series with relay Iili but the latter becomes energized and closes a self-'interrupting' circuit for stepping the stepeby-switch 9| until the sixth Wiper thereof engages the bank contact which is grounded through the eighth wiper of the switch 92. The switches 9| and 92v then have their wipers in corresponding positions to jointly control the circuits of the numbering machine NMi to be operated and the contacts of the distributor 93; Ground potential on the sixth wiper of switch 9| applied directly through the right handA 5 armature and front contact of relay IM to the winding of relay 98- causes said relay 98 to become energized thereby shunting the relay |f9'Iy to cause switch 9| tov stop stepping. The energi-zation of relay 98 transfers the start circuit through its right hand outer armature and front contact to the second distributor inv case another numbering machine is operated before the distributor 93 is released. A circuit is now closed through the second left hand armature and back contact of relay 84, the windingofrelay 95, conductor |98, the fourth-switch wiper of switch 9|, the windingl of relay |93, the second right hand armature and front contact of relay 98,- the left hand inner armature and frontcontact and left hand winding of relay 99 to battery, whereupon relay 95 becomes energizedto open the startv circuitincludingtheV conductor 95 and remove idlel batteryfrom the line circuit. The 1n`e"circuit no'W extends tlir'g'li the normally 'I0 closed contacts f ,thnake-be'fore-break contacts associated with the biit'er'right hand armature of relay 84, c'oridubtor No. AGrof the cable |09, the seventh 'switch wiper f switch 92, the inner right hand armature and front contact of "relay es and the yrest 'contati-.s ef the distributor 93. The yclutch lmagnet circuit of the distributor 93 is closed throiighjtheiefthand outer armature and front contact ofvrfelay |93 to ground at the first switch `r'vigp'r of switch 9|.- The operation of thedistributor 9 3 closes a stepping circuit for the numbering machine NMI through the right hand ar'r'iature and back contact of relay 83, the second switch wiper of switch 9|, the second leitwliand -armatureand front contact of relay |93,mar 1d the contacts ||`I of the distributor, Thenvmbefreimchines may be simil-ar to those disclosed inA the patent to Dirkes et a1.2,193,809pgranted/Maren 19, 1940 (Figs. 17 to 20). The numbering machine operates as described-in said patent to transmit a series of code combi-nationst the line including the number of thermessa'g'e to ,the'particular destination selected, The series of code combinations transmitted by the numbering ina-chine also includes as the rst three elements of said series three unshift code cdribiriations. This operates to transmit the message to the printer |5|, Fig. 5. On the other hand the numbering machines NM2, NMS send as the rst three elements of the series 0f cod ornbinatOfrS, slhft unshft, unshift, which is operative als" will be explained below to' select the reperfdrator (6| in the case of messages being transmitted over line L2 or L3.

As the numbering machine steps in the tenth character, the control contacts II2 close to connect battery through the conductor ||3, the third switch wiper of the vjsw'i'tch 91|, and the left hand inner armature and front contact of relay |93, to the iviindfrngf of relayl I M, whereupon said relay becomes energized andrlocks up through its left hand armature' and front contact to battery at the' left hand armature and'- front contact of relay 98. Immediately following the i'fth pulse of the tenth character the -clos'ure of the contacts ||6 of the vdistriicautor 93 closes la circuit through the right hand armature4 and front contact of relay H4', the fifth switz'zh-wiperv of switch 9|, conductor I |"I and the' winding ofrelay 84 to battery Whereupon relay8v'4 becomes energized.' The energization of relay 84" switchesthe line circuit from the numbering machine throii'gh the right hand outer armature of said relay to the tip 'f the jack l.lI and causes' the operation of `relay 53 in the cord circuit to start' the'oper'ation oi the tape transmitter 2|' in the-manner described above. The energizationA-of relay "81|i opensatits second left hand'varmature andi-back; contact the operating circuits of relays 95 and- |F03 and the holding circuit of re1'ay'9'9', whereupon-the distributor control and numbering maeh'in'e ycircuitsy are restored to normal. Relay' 1|04"is` a slow releals'erelay in'order to delay thev release vofrelay 98` until the cam shaft-'of' the' distributor 9'`has'co'me'torest. Relay 99 is now in readiness t Arespond to a` request for connection to some 4other" sending circuit whereby' thedistribut'or 93 may be utilized by another numbering/machine;

At the terr'nina'torii or tl'ieimelssage, relay 5| becomes' 'dieenergized'v asi .de sicr'ibedv above, thereby opening-circuitsthrough* the ring contact of the plug and jack vwhich' causes" relay 82l to' release. The release of relay 82` opensat/ its second right hand armature and front'l 'contact'. the locking circuit of rlayffl vvilrii'poisadrelay ibecomes 11 deenergized and connects line battery at the contacts of relay 95 to the line circuit Ll. The sending circuit is now in readiness to operate when another circuit is plugged into a jack connected in multiple with the jack 4 I If desired, electromagnetic counters |20 may be connected to contacts |2| of the numbering machine to indicate the actual number last transmitted by said machine. The counters |20 may be disposed on the switchboard or within view of the operator in order to make it possible for the operator to number the message blanks at the transmitting oflice in accordance with the numbers transmitted over the line.

Receiving circuit and Zine selector At the remote oice or station (Fig. 5), the line circuit LI terminates at the printer |5| but may be transferred by the energization of relay |52 in a manner to be described hereinafter to the printer perforator IBI. The perforator |6| and associated tape transmitter constitute a signal repeater for storing and retransmitting messages between lines LI and L2 or LI and L3.

The printer |5| is provided with contacts which are closed upon the receipt of predetermined code combinations such as the shift and unshift code combinations as indicated. For example these contacts may be operated by the pull bars or elements connected to said bars in the usual manner. The printer is also provided with other contacts labeled common contacts which are closed during each cycle of operation of the printer for a period which overlaps the momentary closure of the shift and unshift contacts. Similarly, the printer perforator |6| may be provided with selectively operable contacts closed upon the receipt of the carriage return" code combination, for example in the manner disclosed in the patent to Dirkes et al. 2,143,828, granted January 10, 1939 (see Figs. 8 and 9). The printer perforator |6| is further provided with a pair of contacts |62 operated for example by the punch bar to be closed during each cycle of operation of the perforator.

If the message is preceded by three unshift code combinations transmitted as described above by the automatic code transmitter NMI, the line circuit remains connected to the printer |5| which receives the message. On the other hand if the message is preceded by a shift code combination followed by two unshift code combinations, the relay |52 becomes energized and transfers the line circuit through its third left hand armature and make contact to the printer perforator |6|, connecting the printer |5| to battery through the outer left hand armature and make contact of said relay. It will be apparent that the receipt of the first shift code combination closes a circuit from ground through the shift contacts of the printer I5I, the second left hand armature and back contact of relay |52, the outer left hand armature and back contact of relay |53, the winding of relay |54 and the inner armature and back contact of relay |55 to battery whereupon relay |54 becomes energized. When the shift contact at the printer opens, relay |54 locks up through its armature and front contact and the right hand winding of relay |53, whereupon relay |53 also becomes energized. If the next contact is anything except |53 and |54|when the common contacts of the printer open. If, however, the second code combination is an unshift code combination, the closure of the unshift contacts of the printer |5I closes a circuit through the right hand armature and front contact of relay |53 for energizing relay |52 to transfer the line circuit to the printer perforator |6|. An additional unshift code combination is sent in order to prevent any possibility of the printer perforator dropping or mutilating the first character of the message. Relay |52 remains locked up through its inner /right hand armature and front contact to the right hand switch wiper of the step-by-step switch |56 during the transmission of the message.

At the end of the message, the receipt of the end-of-message signal consisting of two carriage return code combinations and six unshifts causes the line circuit to be transferred back to the printer |5| by the release of relay7 |52. When the carriage return contacts of the perforator |6| close, a circuit is closed through the common contacts and carriage return contacts of the perforator I6 I, second left hand armature and frontcontact of relay |52, the left hand outer armature and back contact of relay |53, the winding of relay |54 and the inner armaturel and back contact of relay |55 whereupon relay |54 becomes energized and locks up in series with the right hand winding of relay V| 53 when the carriage return contacts of the perforator open. The receipt of a single carriage return code combination followed by a diierent code combination releases relays |53 and |54 in an obvious manner. However, if the first carriage return code combination is followed by a second identical code combination, a circuit is closed through contacts of the perforator |6|, the second left hand armature and front contact of relay |52, the outer left hand armature and front contact of relay |53, the winding of relay |51 and the inner left hand armature and front contact of relay |52 to battery, whereupon relay |51 becomes energized. When the punch hammer or common contacts |62 of the perforator |6| close, a circuit is closed through said contacts, the outer right hand armature and front contact of relay |52, the left hand armature and back contact of relay |58, the inner left hand armature and front contact and left hand winding of relay |53, and the winding of relay |55, whereupon relay |55 becomes energized. The operation of relay |55 releases relays |53 and |54, and when relay |55 releases at the end of the carriage return, thereby removing ground from the right hand terminal of the winding of relay |58, relay l|58 becomes energized in series with relay |51.

Upon the receipt of the next code combination which may be assumed to be the unshift code combination, the closure of the punch hammer contacts of perforator |6| closes a circuit through the right hand outer armature and front contact of relay |52 and the left hand armature and front contact of relay |58 for reoperating relay |55. The energization of relay 55 closes a circuit through its outer armature and front contact and the right hand armatures and front contacts of relay |58 for energizing the stepping magnet of the switch |56 and the wipers of said switch take their rst step upon the deenergization of the stepping magnet. In a similar manner the intermittent closure of the punch hammer contacts of perforator |6| upon the receipt of the following code combinations effects the continued 'stepping of the switch |56 'until the yiivilers engage their sixth contacts. When the right hand switch wiper of the switch |56 engages its 'sixth bank contact, the locking circuit of relay |52 is opened and said relay becomes deenergized. The deenergization of relay |52 opens the circuits of relays |51 and |58 and said relays are also released. However, the switch |56 'takes one additional step by reason of the circuit closed through the left hand switch wiper in engagement with its sixth bank contact, 'the interrupter contacts of said switch and the right hand outer armature and back Contact of relay |58 for energizing the stepping magnet of the switch. Thus `it will be seen that at the end of each message which has been switched to the printer perfor-ator IBI, the line is switched back to the printer |5|.

Assume that the message received on the printer periorator |6| is to be Atransmitted over the line L2. The local operator notes the destination of the message and .actuates the threeposition locking key y|8| 'to close its upper set of contacts. The keyboards |12 and |13 have their contacts connected in series relation tothe lines L2 and L3 respectively so that when the switches |82 and 83 are in the positions shown, the operation of either keyboard transmits signals over the corresponding lines L2 and L3. In order to release the keyboard and permit transmission over the lines L2 or L3 from the tape transmitter the switches |82 and |83 are actuated to their alternate positions and the 'subsequent actuation of the key |8| connects the tape transmitter to one or the other of said lines.

Upon the closure of the upper set of `contacts of the key |8| and assuming that the switch |82 has been operated to release line L2 and connect battery and ground to the -contacts lor relays |63 and mit, a circuit is closed 'through thewinding of relay itt, the right hand armature and back contact of relay |63, the upper contacts `'of the key |32', the left hand armature and back contact of the transmitter holding relay |65,'and the second upper set of contacts of 4key |8| to ground, whereupon relay |66 becomes energized. If the wiper i' or' the allotter switch |61 is not Yin engagement with its bank contact corresponding to the position shown, a circuit is -closed to the Istepping magnet and interrupter 'contacts of the switch el and the armature 'and front contact of relay 551i to ground at the switch vr|82 to drive the switch iti. When the wiper vo'f the switch |61 reaches the position shown, 'a circuit is :closed from ground through said wiper, the right hand inner armature and back contact of relay r|65, theright hand winding of the transmitter 'start relay "|66, the nith set of contacts of the key 18|, the left hand inner armature and back contact lof relay |63 and the switch |82 to battery, whereupon relay itt becomes energized and closes the sending circuit itil from the distributor transmitter |69, through the right hand-outer larmature and iront contact of said relay, the third set of contacts of the key ISI and the left Yhand outer armature and iront Contact of relay |63. Relay |63 becomes energized in response tothe energization of relay |66 through a circuit 'that may b'e traced through the fourth setv of contacts of the key 8|, the left hand winding and left hand inner armature and front contact of relay 166110 ground on the conductor |11) whic'his grounded lat the distributor |69 until the end ofthe message, in a similar manner tothe operation of the distributor and control .relays in the cord circuit .of (Fig. ,2.

The energization of relay |66 also closes a circuit through the outer left hand armatures and front contacts thereof for energizing the clutch magnet of the distributor |69 and relay |65. Relay iti becomes locked up through its left hand armature and front contact to ground at the second set of contacts of the key |8| and closes the circuit of the lamp |15 through its right hand outer armature and vfront contact, said lamp .remaining lighted until relay |66 is released at the end of the message. The energization of relay |53 lights the busy lamp |16 at the keyboard to indicate to the operator that transmission toa line is being effected through the repeater equipment. The tape transmitter |1| may be connected to line L3 in a similar manner by actuating the key I8! to close the lower set of contacts. When the transmission of Aa message is completed, the operator restores the key |'8| after noting that the lamp |15 has been extinguished thereby releasing the line and the associated control relays. It will be noted that even 'if 'the switch i 82 or |83 is restored to the position shown during transmission from the tape transmitter |1|, the operation of the tape transmitter is not affected and the keyboard |12 or |13 cannot be utilized to transmit to the line which is in use since the contacts of said keyboard .are short circuited by the left hand outer armature and front contact of relay w3 or |63a.

Various modications in the vsystem shown and described for the purpose of explaining the invention will occur to those skilled in the art and may be made without departing from the scope of the invention as dened in the appended claims.

We claim:

1. A telegraph exchange system comprising a first ofi-ice, a second ouce remote from said first ofce, a line or channel connecting said yomces, said line or channel having a plurality of terminals at said rst cnice and terminating in selective switching equipment at said second office, means at the rst oiiice for extending calls to said line or channel and means automatically controlled by the particular line terminal selected at said rst office in switching through a call for directively controlling said Vselective switching equipment at said second oflice.

2. A telegraph exchange system comprising a rst oiice, a second ooe remote from therst ofiice, a line or channel connecting said oiioes, printing telegraph apparatus at said oiflces including transmitting means at the rst oce, selective switching equipment at the second oflice for extending calls to any one of a plurality of receiving points, an automatic code transmitter at the rst office, means including said .code transmitter for directively controlling said switching equipment over said line or channel and means for initiating the operation of said code transmitter when a call is made to said second oice over said line or channel.

3. A system as set forth in claim 2 in which means is provided for initiating the operation of the code transmitter upon the connection of the transmitting means at said rst 'office to the line or channel to the second ofce.

,. 4. A system as set forth in claim 2 'in which the line or channel is provided with a plurality of sending terminals at the first ofllce and an automatic code transmitter is operatively associated with each of said terminals and r'arranged to send Adiierent codes 'to variably lrcontrol said selective switching equipment.

'5. A system as set :forth in claim 2 embodying means whereby the code transmitter sends both switch-controlling impulses and service code signals or numbers to the printing telegraph apparatus.

6. In a telegraph system, lines or channels, switching means for selecting a desired oneof said lines or channels, means for numbering successive calls over said lines or channels, means for controlling said numbering means to send consecutive numbers accompanying messages to the same destination even though messages for diierent destinations are sent over the same line or channel and means including said numbering means to control said switching means.

7. A printer selector for connecting a normally inoperative circuit or receiving unit to a transmitting line comprising contacts, means for operating said contacts upon the receipt of a predetermined code combination, other contacts, means for operating said other contacts during each cycle of the printer and circuit-controlling means jointly controlled by said contacts.

8. In a telegraph system, a printer, a line terminating at said printer, a repeater adjacent said printer, means including the printer for switching the line to said repeater and means for switching the line back to said printer at the end of every message sent to the repeater.

9. In a telegraph system, a line, a keyboard transmitter for transmitting over said line, repeating apparatus for repeating printer signals over said line, a manually operable switch for releasing said line from said keyboard transmitter and means for rendering said repeating apparatus operative when said switch is operated and preventing the operation of said keyboard transmitter until the repeating apparatus has completed transmission of a message.

10. A telegraph exchange system comprising an office, outgoing lines or channels from said oce,

printing telegraph transmitting apparatus for transmitting messages over said lines or channels, means including a plurality of service code transmitters operatively associated with a single one of said lines or channels for appending a variable predetermined group of signals to the messages sent over said single line or channel, switching means at the remote end of said single one of said lines or channels and means including one of said service code transmitters for controlling said switching means.

1l. A telegraph exchange system comprising an oice, outgoing lines or channels from said oice, printing telegraph transmitting apparatus for transmitting messages over said lines or channels, means including a code signal generating means associated with a single one of said lines or channels for sending a selecting code accompanying each message sent over said single line or channel, means for successively initiating the operation of said' code signal generating means and means responsive to the selecting codes for switching the messages to different points.

12. A telegraph exchange system comprising an oice, outgoing lines or channels from said oflice, printing telegraph apparatus in said oflice, switching means in said office for selectively connecting said apparatus to said lines or channels, codetransmitting means associated with each of said lines or channels, means for initiating the operation of said code-transmitting means after each connection to a line or channel and means to vary the transmitted code in accordance with the mode of operationof saidswitching means.

13. A telegraphexchange system comprising a plurality of lines or channels, a switchboard containing terminals of said lines or channels, certain of said lines orvchannels having more than one terminal in each section of the switchboard, a plurality of storage transmitters, cord circuits for selectively connecting said transmitters to desired lines or channels at said switchboard,

code transmitters for generating predetermined code signal groups in the respective lines or channels, means for rendering said code transmitters operative when connections are made to said lines or channels, and means for selecting a desired code transmitter for operation in response to the selection of a particular terminal in the case of transmission over one of said certain lines or channels having a plurality of terminals.

14. Line switching mechanism comprising a printer responsive to code impulses, said printer being provided with means for operating contacts only upon the receipt of predetermined code signals and for operating other contacts during each operating cycle of the printer, relays connected to both said contacts and saidA other contacts of the printer, and a line switching device controlled by said relays upon the receipt of predetermined code signals by the printer.

15. Line switching mechanism for a telegraph line comprising a first printer and a second printer responsive to code impulses, a relay arranged to connect said line alternatively to either printer, contacts on both printers and means for operating the same only upon the receipt of predetermined code signals by the operating printer, and means connected to said contacts for controlling the energization and deenergization of said relay.

16. A telegraph system comprising a line, two printers at one end of said line each provided with code-responsive contacts, and means including said contacts for rendering either printer responsive to signals transmitted over the line and excluding the other printer until it is selected.

17. A printing telegraph system comprising a line circuit terminating in a printer, means for transmitting messages separated by switching signals over said line circuit, a reperforator adjacent said printer, means responsive to switching signals for switching the line circuit to said reperforator for some but not all of the messages and for invariably switching the line circuit back to the printer after reception of a message switched to the reperforator and means including said reperforator for repeating messages received thereby.

18. A printing telegraph system comprising an incoming line, an outgoing line, repeating apparatus for retransmitting over said outgoing line signals received over said incoming line, a local transmitter for said outgoing line and means whereby the repeating apparatus controls the local transmitter to prevent interference in case of concurrent operation of said transmitter and said repeating apparatus.

19. The method of operating two telegraph systems, the second of which includes a storage controlled transmitter, which comprises sending from a station on the rst system to a station common to the rst and a second system a series of code Vcombinations including a code combination designed to identify a station of the second system together with each message, causing the code combination to controlv the recording of the message at the common station when the code combination identifies the common station, and causl ing the storage of the message in the storage of the storage controlled transmitter of the second system when the code combination identifies some station of the second system other than the common station.

20. A combination of signaling equipment cornprising an incoming transmission channel supplying permutation codes including directing codes and message codes, a plurality of recording instruments capable of recording said message codes, means normally associating one of said instruments with said source for recording of incoming message codes, selective switching means controlled by one of said instruments in response to directing code combinations for disassociating said one instrument from operative association with said source and associating the other therewith, and means including means responsive to an end-of-message signal for returning said one instrument to the normal association with said channel. y

GEORGE G. LIGHT. WILLIAM B. BLANTON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number l Name Date 1,681,039 I-omrighous Aug. 14, 1928 2,023,952 Dirkes Dec. 10, 1935 2,122,367 Dirkes June 28, 1938 2,143,828 Dirkes Jan. 10, 1939 2,174,731 Dirkes Oct. 3, 1939 2,193,810 Wheeler Mar. 19, 1940 2,193,812 Blanton Mar. 19, 1940 2,193,967 Kleinschmidt Mar. 19, 1940 2,227,121 Blanton Dec. 31, 1940 

